This invention relates generally to milling machine tools and more specifically, this invention relates to a milling machine having a numerically controlled adjustable arbor to enable automatic adjustment of the width between arbor milling cutters carried on the arbor thereby facilitating random workpiece machining.
One of the most common metal working operations employed in the production of machined parts is that of milling whereby a rotary driven cutting tool is brought into contact with the surface of a workpiece to shave metal therefrom. Milling machines which are generally employed to carry out milling operations have a rotary driven spindle for rotatably driving the milling cutter and a movable table for supporting the workpiece and for moving the workpiece into operative engagement with the milling cutter. Small and moderate size milling cutters are usually carried on a toolholder which is inserted directly into the milling machine spindle so as to be rotatably driven thereby. When larger milling cutters are to be employed, securing the milling cutter to a toolholder for insertion into the spindle becomes impractical. Instead, the large milling cutter is coaxially carried on an arbor which is secured at one end to the machine tool spindle and is rotatably supported at its other end on the machine tool by one or more arbor supports in coaxial alignment with the spindle. Usually, with conventional milling machine arbor set ups such as described above, the arbor can carry more than one large milling cutter at a time. Often, it is desirable to employ two or more large milling cutters in spaced apart relationship for performing straddle milling operations in which the workpiece is milled by the two spaced-apart milling cutters which thus straddle portions of the workpiece, giving rise to the term "straddle milling".
In the past, operator intervention has been required to adjust the distance between milling cutters on the arbor to facilitate different straddle milling operations on random workpieces. Typically, in order to adjust the cutter spacing, the machine has to be stopped and the operator has to remove an arbor support and change the spacers on the arbor between the cutters on the arbor so as to alter the spacing between the cutters. Once the milling cutters on the arbor have been respaced on the arbor, the arbor support is reassembled and the arbor support is re-engaged with the arbor before the machine is restarted. All during the time that this occurs, machine part production has been interrupted, causing an increase in machine idle time.
In an effort to eliminate the need to manually adjust the width between milling cutters on the arbor of the milling machine to enable different straddle milling operations on random workpieces, the present invention discloses a machine tool having a numerically controlled adjustable arbor set up which allows for automatic control of the width of arbor milling cutters responsive to N/C commands, thereby eliminating the need for operator intervention when machining random workpieces.
It is therefore an object of the present invention to provide a machine tool having a numerically controlled adjustable arbor set which allows automatic adjustment of the width between arbor milling cutters responsive to numerical control commands.
It is yet another object of the present invention to provide a milling machine having a numerically controlled, adjustable arbor which allows automatic adjustment of the arbor milling cutters responsive to numerical control commands while the arbor is rotatably driven by the spindle.
Other objects of the invention will become apparent from the description of the invention provided hereinafter.